Lemonldap::NG::Portal versions from 2.0.0 before 2.16.9, from 2.17.0 before 2.21.5, from 2.22.0 before 2.23.3 for Perl allow authentication bypass via an OAuth2 state parameter stored as an SSO session in the GitHub and LinkedIn backends.

Before redirecting to the identity provider, extractFormInfo() creates the state session with the positional call getApacheSession( undef, 1, 0, 'GitHubState' ). getApacheSession() takes a session id followed by a named argument hash, so the trailing arguments become that hash, kind defaults to SSO, and the state is written to the global session storage as a regular SSO session. Its identifier is handed to the unauthenticated visitor as the state parameter of the redirection URL.

Any visitor who reaches the GitHub or LinkedIn endpoint can replay that identifier as a session cookie and obtain a valid SSO session without authenticating. The session holds neither user nor authenticationLevel, which the shipped bootstrap configuration accepts because it grants virtual hosts a "default => accept" access rule; deployments whose rules test the user or require an authentication level are less exposed. Only configurations with the GitHub or LinkedIn authentication module enabled are affected.

An issue was discovered in LemonLDAP::NG before 2.0.12. There is a missing expiration check in the OAuth2.0 handler, i.e., it does not verify access token validity. An attacker can use a expired access token from an OIDC client to access the OAuth2 handler The earliest affected version is 2.0.4.

An issue was discovered in LemonLDAP::NG before 2.20.1. An Improper Check during session refresh allows an authenticated user to raise their authentication level if the admin configured an "Adaptative authentication rule" with an increment instead of an absolute value.

In LemonLDAP::NG before 2.16.7 and 2.17 through 2.21 before 2.21.3, OS command injection can occur in the Safe jail. It does not Localize during rule evaluation. Thus, an administrator who can edit a rule evaluated by the Safe jail can execute commands on the server.

A cross-site scripting (XSS) vulnerability in LemonLDAP::NG before 2.20.1 allows remote attackers to inject arbitrary web script or HTML via the url parameter of the upgrade session confirmation page (upgradeSession / forceUpgrade) if the "Upgrade session" plugin has been enabled by an admin